Github is now the most popular open source forge, having surpassed Sourceforge, Google Code and CodePlex in total number of commits for the period of January to May 2011, according to data released today by Black Duck Software. This should probably come as no surprise, but it's good to have data to backup assumptions.
During the period Black Duck examined, Github had 1,153,059 commits, Sourceforge had 624,989, Google Code and 287,901 and CodePlex had 49,839.
Black Duck also found that C++ and Java were the most popular languages for commits in these forges during this period of time.
Black Duck didn't look at language specific forges such as RubyForge, and it excluded shell, XML and assembler commits.